Somewhere on the continuum between complexity and incoherence lies the latest film from Steven Soderbergh. After big-time Hollywood critical and box office success with the glossy, classy “Erin Brockovich,” “Traffic,” and “Oceans 11,” Soderbergh has returned to his indie roots to make a small, messy, improvised, non-linear film that recalls his earliest success with “sex, lies, and videotape.” Indeed, he has described the new film, “Full Frontal,” as a thematic sequel.

Like the earlier film, “Full Frontal” is filled with intimate conversations about love, sex, boundaries, longing, and voyeurism. Both films revolve around two sisters, one married, one single, with some strains in their relationship.

But this film is less a story than a series of moments, variations on the themes rather than a narrative. Digital and analog images alternate as we go into and out of a movie within a movie, even a movie within a movie within a movie, performed by actors playing actors.

Several different stories overlap and intersect. Catherine Keener plays Alice, a human resources director unhappily married to Carl (David Hyde Pierce), who writes for a magazine. Alice’s sister, Linda (Mary McCormack) is a masseuse who is currently carrying out an online flirtation with Brian (Rainn Wilson), Carl’s co-author. Both Linda and Brian have not been entirely truthful about themselves, and they are planning to meet in Tucson.

Linda is having an affair with Calvin (Blair Underwood), an actor who is currently playing the part of an actor named Nicholas who is playing the part of a sidekick to a detective played by Brad Pitt (playing himself). In his movie, Nicholas becomes romantically involved with a journalist named Catherine (Julia Roberts in a very unfortunate wig, except when she appears as Francesca, the actress playing Catherine) who happens to work for the same magazine that Alice’s husband Carl works for in what sort of passes for real life in “Full Frontal,” at least as compared to the Nicholas/Catherine movie within a movie or the shlocky cop story with Brad Pitt and Calvin that is the movie within the movie within the movie. Two characters have written a play called “The Sound and the Fuhrer” featuring a high strung and narcissistic actor (brilliantly played by Nicky Katt) as a Hitler who uses a cell phone and breaks up with his girlfriend by explaining that he just needs to “swim in Lake Me for a while.” Then it starts to get confusing.

Themes and images flicker through several levels, like a David Lynch movie with less voluptuous imagery. On one level, a secret letter in a red envelope contains a note ending a marriage. In another story, a secret letter in a red envelope contains a note starting an affair. Alice is firing employees at her company, asking them bizarre questions and tossing an inflated globe at them, as her husband, Carl, is asking bizarre questions of co-workers and getting fired from the magazine. We see Alice in bed with Calvin, who, as the character Nicholas explains to the journalist interviewing him that black men in movies never get to do sex scenes. Alice is turning 41 just as Gus (David Duchovney) the producer of the movie starring Calvin and Francesca, is turning 40, with a party that many of the characters in the movie are invited to attend. In the end, just as one set of fictions are abandoned in favor of reality, a fiction at a deeper level is revealed.

The movie has many wonderful moments and many marvelous lines. But it does not have the improvisational brilliance of the Christopher Guest movies and comes off more like an actor’s studio workshop than a film. The whole is less than the sum of its parts, but some of those parts are remarkably vivid and intriguing.

Parents should know that, as the title indicates, this movie includes explicit nudity, explicit and varied sexual references and situations, and very strong language. A character dies, apparently from auto-erotic asphyxiation. Characters drink and smoke and eat hash brownies. There are tense emotional scenes. Parents may want to see the film themselves before deciding whether it is appropriate for teen viewing.

Families who see the movie should talk about why Soderburgh told the story this way and what a movie they would make with their friends and families would be like.

Viewers who enjoy this movie will enjoy two other movies about making movies and the line between fantasy and reality, The Stunt Man and Day for Night. They may also want to compare this to sex, lies, and videotape.